NAME

srec_intel - Intel Hexadecimal object file format specification

DESCRIPTION

This format is also known as the IntelMCS-86Object format.
This document describes the hexadecimal object file format for the
Intel 8-bit, 16-bit, and 32-bit microprocessors. The hexadecimal
format is suitable as input to PROM programmers or hardware emulators.
Hexadecimal object file format is a way of representing an absolute
binary object file in ASCII. Because the file is in ASCII instead of
binary, it is possible to store the file is non-binary medium such as
paper-tape, punch cards, etc.; and the file can also be displayed on
CRT terminals, line printers, etc.. The 8-bit hexadecimal object file
format allows for the placement of code and data within the 16-bit
linear address space of the Intel 8-bit processors. The 16-bit
hexadecimal format allows for the 20-bit segmented address space of the
Intel 16-bit processors. And the 32-bit format allows for the 32-bit
linear address space of the Intel 32-bit processors.
The hexadecimal representation of binary is coded in ASCII alphanumeric
characters. For example, the 8-bit binary value 0011-1111 is 3F in
hexadecimal. To code this in ASCII, one 8-bit byte containing the
ASCII code for the character ’3’ (0011-0011 or 0x33) and one 8-bit byte
containing the) ASCII code for the character ’F’ (0100-0110 or 0x46)
are required. For each byte value, the high-order hexadecimal digit is
always the first digit of the pair of hexadecimal digits. This
representation (ASCII hexadecimal) requires twice as many bytes as the
binary representation.
A hexadecimal object file is blocked into records, each of which
contains the record type, length, memory load address and checksum in
addition to the data. There are currently six (6) different types of
records that are defined, not all combinations of these records are
meaningful, however. The record are:
· Data Record (8-, 16-, or 32-bit formats)
· End of File Record (8-, 16-, or 32-bit formats)
· Extended Segment Address Record (16- or 32-bit formats)
· Start Segment Address Record (16- or 32-bit formats)
· Extended Linear Address Record (32-bit format only)
· Start Linear Address Record (32-bit format only)
GeneralRecordFormat
+-------+--------+--------+--------+------+----------+
|Record | Record | Load | Record | Data | Checksum |
|Mark | Length | Offset | Type | | |
+-------+--------+--------+--------+------+----------+
Record Mark.
Each record begins with a Record Mark field containing 0x3A,
the ASCII code for the colon (‘‘:’’) character.
Record Length
Each record has a Record Length field which specifies the
number of bytes of information or data which follows the Record
Type field of the record. This field is one byte, represented
as two hexadecimal characters. The maximum value of the Record
Length field is hexadecimal ’FF’ or 255.
Load Offset
Each record has a Load Offset field which specifies the 16-bit
starting load offset of the data bytes, therefore this field is
only used for Data Records. In other records where this field
is not used, it should be coded as four ASCII zero characters
(‘‘0000’’ or 0x30303030). This field is two byte, represented
as four hexadecimal characters.
Record Type
Each record has a Record Type field which specifies the record
type of this record. The Record Type field is used to
interpret the remaining information within the record. This
field is one byte, represented as two hexadecimal characters.
The encoding for all the current record types are:
0 Data Record
1 End of File Record
2 Extended Segment Address Record
3 Start Segment Address Record
4 Extended Linear Address Record
5 Start Linear Address Record
Data Each record has a variable length Data field, it consists of
zero or more bytes encoded as pairs of hexadecimal digits. The
interpretation of this field depends on the Record Type field.
Checksum
Each record ends with a Checksum field that contains the ASCII
hexadecimal representation of the two’s complement of the
8-bit bytes that result from converting each pair of ASCII
hexadecimal digits to one byte of binary, from and including
the Record Length field to and including the last byte of the
Data field. Therefore, the sum of all the ASCII pairs in a
record after converting to binary, from the Record Length field
to and including the Checksum field, is zero.
ExtendedLinearAddressRecord
(32-bit format only)
+--------+--------+--------+--------+-----------+----------+
|Record | Record | Load | Record | ULBA | Checksum |
|Mark | Length | Offset | Type | (2 bytes) | |
|(‘‘:’’) | (2) | (0) | (4) | | |
The-32-bit-Extended-Linear-Address-Record-is-used-to-specify bits 16-31
of the Linear Base Address (LBA), where bits 0-15 of the LBA are zero.
Bits 16-31 of the LBA are referred to as the Upper Linear Base Address
(ULBA). The absolute memory address of a content byte in a subsequent
Data Record is) obtained by adding the LBA to an offset calculated by
adding the Load Offset field of the containing Data Record to the index
of the byte in the Data Record (0, 1, 2, ... n). This offset addition
is done) modulo 4G (i.e. 32-bits from 0xFFFFFFFF to 0x00000000) results
in wrapping around from the end to the beginning of the 4G linear
address defined by the LBA. The linear address at which a particular
byte is loaded is calculated as:
(LBA + DRLO + DRI) MOD 4G
where:
DRLO is the Load Offset field of a Data Record.
DRI is the data byte index within the Data Record.
When an Extended Linear Address Record defines the value of LBA, it may
appear anywhere within a 32-bit hexadecimal object file. This value
remains in effect until another Extended Linear Address Record is
encountered. The LBA defaults to zero until an Extended Linear Address
Record is encountered. The contents of the individual fields within
the record are:
Record Mark
This field contains 0x3A, the hexadecimal encoding of the ASCII
colon (‘‘:’’) character.
Record Length
The field contains 0x3032, the hexadecimal encoding of the
ASCII characters ‘‘02’’, which is the length, in bytes, of the
ULBA data information within this record.
Load Offset
This field contains 0x30303030, the hexadecimal encoding of the
ASCII characters ‘‘0000’’, since this field is not used for
this record.
Record Type
This field contains 0x3034, the hexadecimal encoding of the
ASCII character ‘‘04’’, which specifies the record type to be
an Extended Linear Address Record.
ULBA This field contains four ASCII hexadecimal digits that specify
the 16-bit Upper Linear Base Address value. The value is
encoded big-endian (most significant digit first).
Checksum
This field contains the check sum on the Record Length, Load
Offset, Record Type, and ULBA fields.
ExtendedSegmentAddressRecord
(16- or 32-bit formats)
+--------+--------+--------+--------+-----------+----------+
|Record | Record | Load | Record | USBA | Checksum |
|Mark | Length | Offset | Type | (2 bytes) | |
|(‘‘:’’) | (2) | (0) | (2) | | |
The-16-bit-Extended-Segment+Address-Record-is-used-to-specify bits 4-19
of the Segment Base Address (SBA), where bits 0-3 of the SBA are zero.
Bits 4-19 of the SBA are referred to as the Upper Segment Base Address
(USBA). The absolute memory address of a content byte in a subsequent
Data Record is) obtained by adding the SBA to an offset calculated by
adding the Load Offset field of the containing Data Record to the index
of the byte in the Data Record (0, 1, 2, ... n). This offset addition
is done modulo 64K (i.e. 16-bits from 0xFFFF to 0x0000 results in
wrapping around from the end to the beginning of the 64K segment
defined by the SBA. The address at which a particular byte is loaded
is calculated as:
SBA + ((DRLO + DRI) MOD 64K)
where:
DRLO is the LOAD OFFSET field of a Data Record.
DRI is the data byte index within the Data Record.
When an Extended Segment Address Record defines the value of SBA, it
may appear anywhere within a 16-bit hexadecimal object file. This
value remains in effect until another Extended Segment Address Record
is encountered. The SBA defaults to zero until an Extended Segment
Address Record is encountered.
The contents of the individual fields within the record are:
Record Mark
This field contains 0x3A, the hexadecimal encoding of the ASCII
colon (‘‘:’’) character.
Record Length
The field contains 0x3032, the hexadecimal encoding of the
ASCII characters ’02’, which is the length, in bytes, of the
USBA data information within this record.
Load Offset
This field contains 0x30303030, the hexadecimal encoding of the
ASCII characters ’0000’, since this field is not used for this
record.
Record Type
This field contains 0x3032, the hexadecimal encoding of the
ASCII character ‘‘02’’, which specifies the record type to be
an Extended Segment Address Record.
USBA This field contains four ASCII hexadecimal digits that specify
the 16-bit Upper Segment Base Address value. The field is
encoded big-endian (most significant digit first).
Checksum
This field contains the check sum on the Record length, Load
Offset, Record Type, and USBA fields.
DataRecord
(8-, 16- or 32-bit formats)
+--------+--------+--------+--------+------+----------+
|Record | Record | Load | Record | Data | Checksum |
|Mark | Length | Offset | Type | | |
|(‘‘:’’) | | | | | |
The-Data-Record-provides-a-set-of-hexadecimal-digits-that represent the
ASCII code for data bytes that make up a portion of a memory image.
The method for calculating the absolute address (linear in the 8-bit
and 32-bit case and segmented in the 16-bit case) for each byte of data
is described in the discussions of the Extended Linear Address Record
and the Extended Segment Address Record.
The contents of the individual fields within the record are:
Record Mark
This field contains 0x3A, the hexadecimal encoding of the ASCII
colon (‘‘:’’) character.
Record Length
The field contains two ASCII hexadecimal digits that specify
the number of data bytes in the record. The maximum value is
255 decimal.
Load Offset
This field contains four ASCII hexadecimal digits representing
the offset from the LBA (see Extended Linear Address Record see
Extended Segment Address Record) defining the address which the
first byte of the data is to be placed.
Record Type
This field contains 0x3030, the hexadecimal encoding of the
ASCII character ‘‘00’’, which specifies the record type to be a
Data Record.
Data This field contains pairs of ASCII hexadecimal digits, one pair
for each data byte.
Checksum
This field contains the check sum on the Record Length, Load
Offset, Record Type, and Data fields.
StartLinearAddressRecord
(32-bit format only)
+--------+--------+--------+--------+-----------+----------+
|Record | Record | Load | Record | EIP | Checksum |
|Mark | Length | Offset | Type | (4 bytes) | |
|(‘‘:’’) | (4) | (0) | (5) | | |
The-Start+Linear-Address-Record-is-used-to-specify-the-execution start
address for the object file. The value given is the 32-bit linear
address for the EIP register. Note that this record only specifies the
code address within the 32-bit linear address space of the 80386. If
the code is to start execution in the real mode of the 80386, then the
Start Segment Address Record should be used instead, since that record
specifies both the CS and IP register contents necessary for real mode.
The Start Linear Address Record can appear anywhere in a 32-bit
hexadecimal object file. If such a record is not present in a
hexadecimal object file, a loader is free to assign a default start
address.
The contents of the individual fields within the record are:
Record mark
This field contains 0x3A, the hexadecimal encoding of the ASCII
colon (‘‘:’’) character.
Record length
The field contains 0x3034, the hexadecimal encoding of the
ASCII characters ‘‘04’’, which is the length, in bytes, of the
EIP register content within this record.
Load Offset
This field contains 0x30303030, the hexadecimal encoding of the
ASCII characters ‘‘0000’’, since this field is not used for
this record.
Record Type
This field contains 0x3035, the hexadecimal encoding of the
ASCII character ‘‘05’’, which specifies the record type to be a
Start Linear Address Record.
EIP This field contains eight ASCII hexadecimal digits that specify
the 32-bit EIP register contents. The field is encoded big-
endian (most significant digit first).
Checksum
This field contains the check sum on the Record length, Load
Offset, Record Type, and EIP fields.
StartSegmentAddressRecord
(16- or 32-bit formats)
+--------+--------+--------+--------+------------+------------+----------+
|Record | Record | Load | Record | CS (2 | IP (2 | Checksum |
|Mark | Length | Offset | Type | bytes) | bytes) | |
|(‘‘:’’) | (4) | (0) | (3) | | | |
The-Start+Segment-Address-Record-is-used-to-specify-the-execution-start--+
address for the object file. The value given is the 20-bit segment
address for the CS and IP registers. Note that this record only
specifies the code address within the 20-bit segmented address space of
the 8086/80186. The Start Segment Address Record can appear anywhere
in a 16-bit hexadecimal object file. If such a record is not present
in a hexadecimal object file, a loader is free to assign a default
start address.
The contents of the individual fields within the record are:
Record Mark
This field contains 0x3A, the hexadecimal encoding of the ASCII
colon (‘‘:’’) character.
Record Length
The field contains 0x3034, the hexadecimal encoding of the
ASCII characters ‘‘04’’, which is the length, in bytes, of the
CS and IP register contents within this record.
Load Offset
This field contains 0x30303030, the hexadecimal encoding of the
ASCII characters ‘‘0000’’, since this field is not used for
this record.
Record Type
This field contains 0x3033, the hexadecimal encoding of the
ASCII character ’03’, which specifies the record type to be a
Start Segment Address Record.
CS This field contains four ASCII hexadecimal digits that specify
the 16-bit CS register contents. The field is encoded big-
endian (most significant digit first).
IP This field contains four ASCII hexadecimal digits that specify
the 16-bit IP register contents. The field is encoded big-
endian (most significant digit first).
Checksum
This field contains the check sum on the Record length, Load
Offset, Record Type, CS, and IP fields.
EndofFileRecord
(8-, 16-, or 32-bit formats)
+--------+--------+--------+--------+----------+
|Record | Record | Load | Record | Checksum |
|Mark | Length | Offset | Type | (0xFF) |
|(‘‘:’’) | (0) | (0) | (1) | |
The-End-of-File-Record-specifies-the+-end--of--the hexadecimal object
file.
The contents of the individual fields within the record are:
Record mark
This field contains 0x3A, the hexadecimal encoding of the ASCII
colon (‘‘:’’) character.
Record Length
The field contains 0x3030, the hexadecimal encoding of the
ASCII characters ‘‘00’’. Since this record does not contain
any Data bytes, the length is zero.
Load Offset
This field contains 0x30303030, the hexadecimal encoding of the
ASCII characters ‘‘0000’’, since this field is not used for
this record.
Record Type
This field contains 0x3031, the hexadecimal encoding of the
ASCII character ‘‘01’’, which specifies the record type to be
an End of File Record.
Checksum
This field contains the check sum an the Record Length, Load
Offset, and Record Type fields. Since all the fields are
static, the check sum can also be calculated statically, and
the value is 0x4646, the hexadecimal encoding of the ASCII
characters ‘‘FF’’.
SizeMultiplier
In general, binary data will expand in sized by approximately 2.3 times
when represented with this format.

EXAMPLE

Here is an example Intel hex file. It contains the data ‘‘Hello,
World’’ to be loaded at address 0.
:0D00000048656C6C6F2C20576F726C640AA1
:00000001FF

REFERENCE

COPYRIGHT

srec_cat version 1.39
Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
2007, 2008 Peter Miller
The srec_cat program comes with ABSOLUTELY NO WARRANTY; for details use
the ’srec_cat-VERSionLicense’ command. This is free software and you
are welcome to redistribute it under certain conditions; for details
use the ’srec_cat-VERSionLicense’ command.

AUTHOR

Peter Miller E-Mail: millerp@canb.auug.org.au
/\/\* WWW: http://www.canb.auug.org.au/~millerp/Derivation
This manual page is derived from a file marked as follows:
Intel Hexadecimal Object File Format Specification; Revision A, 1/6/88
Disclaimer: Intel makes no representation or warranties with respect to
the contents hereof and specifically disclaims any implied warranties
of merchantability or fitness for any particular purpose. Further,
Intel reserves the right to revise this publication from time to time
in the content hereof without obligation of Intel to notify any person
of such revision or changes. The publication of this specification
should not be construed as a commitment on Intel’s part to implement
any product.